“best” bike vehicle – van. No question.
Best vehicle if you also commute to work in it, need a certain type of vehicle for work use, have family to transport around, do other non-bike related long journeys (fuel consumption, motorway speed).. it gets a lot more complicated.
Personally, large hatchback/small estate, with the ability to carry on the roof or in the boot.
Shortish trip and its muddy, on the roof. Long journey, security if you stop at a motorway services, in the back.
Drives better than any van, even the car like ones; better mpg and lower tax.